Non-condensible gas removal system for refrigerant units



Feb. 14, 1961 T. s. PARKER 2,971,352

NON-CONDENSIBLE GAS REMOVAL SYSTEM FOR REFRIGERANT UNITS Filed April 7,1958 1 COMPRESSOR INVENTOR.

7270/! S S. PAR/(5E BY 574/714 MLSOM LEW/s sflgmg N ON-CONDENSIBLE GASREMOVAL SYSTEM FOR REFRIGERANT UNITS Thomas S. Parker, 1218 MelbourneAve., Dallas, Tex.

Filed Apr. 7, 1958, Ser. No. 726,988

10 Claims. (Cl. 62-475) This invention relates to a refrigeration systemand particularly to mechanism for removing oil and non-condensible gasesfrom the refrigerant.

Objects of the invention are to provide oil and gas removal mechanismwherein:

(1) The design of the mechanism is such as to eliminate certain oilseparators, separator heaters, separator heater thermostats, suction anddischarge valves, driving motors, solenoid valves, motor starters,relays switches and pilot lights heretofore employed, and

(2) The mechanism is relatively compact, requires minimum maintenance,employs a minimum of wiring at the plant and'in the field, eliminatesacid generation in the system, and makes possible the attainment of ahermetically sealed centrifugal compressor unit.

Other objects of this invention will appear in the following descriptionand appended claims, reference being had to the accompanying drawingsforming a part of this specification wherein like reference charactersdesignate corresponding parts in the several views.

In the drawings:

Fig. 1 is a schematic view of a refrigerating system having theinvention incorporated therein.

Fig. 2 is a sectional view illustrating an alternate vaporizingmechanism which may be employed in the Fig. 1

system.

Before explaining the present invention in detail, it is to beunderstood that the invention is not limited in its application to thedetails of construction and arrangement of parts illustrated in theaccompanying drawings, since the invention is capable of otherembodiments and of being practiced or carried out in various ways. Also,it is to be understood that the phraseology or terminology employedherein is for the purpose of description and not of limitation.

In the drawings there is shown a refrigerating system including acentrifugal compressor 10, which may be a multiple stage unit as shownin US. Patent No. 2,759,- 662 or a single stage unit. The constructionof the unit is such as to deliver freon or other refrigerant vaporthrough line 12 to a condenser 14.

Condenser 14 comprises a shell 16 containing two circular tube sheets 18and 20 for supporting heat exchange tubes 21. A partition 22 extendsfrom sheet 18 to the adjacent end wall of the shell. In operation,cooling water from inlet pipe 24 passes through the upper ones of heatexchange tubes 21 in the arrow 26 direction, and then flows through thelower ones of the heat exchange tubes I in the arrow 28 direction so asto be exhausted through outlet pipe 35. As the water flows through theheat exchange tubes it liquifies the refrigerant vapor passing over thetubes from line 12. The liquified refrigerant settles in the bottom ofshell 16, from where it passes through line 32 and a liquid seal (notshown) to an evaporator 33.

Evaporator 33 comprises a cylindrical shell 35 containing tube sheets 36and 37 for supporting finned heat exchange tubes 38. A partition 39extends from sheet td States Patent 6 F 2,971,352 Patented Feb. 14, 196136 to the adjacent end wall of the shell. In operation, heat exchangefluid from inlet pipe 40 is circulated through tubes 38 and out throughoutlet pipe 41 so as to vaporize the refrigerant from pipe 32. Thevaporized refrigerant passes over tubes 38 and through an eliminator 42and into a line 43 leading to the inlet for compressor 10.

Condenser shell 16 connects with a line 45, which serves to conduct anon-condensible gas, oil and refrigerant vapor mixture from the upperportion of the condenser shell where it tends to collect duringoperation of the system. Line 45 leads to a positive displacement vacuumpump 46 located within an oil tank 47. Pump 46 is driven by a motor 79,which also drives lubricant pump 78. The outlet for pump 46 is connectedto a line 48, which leads to a spray pipe 50 located within a purge drum51.

In operation, pump 46 acts to pump the non-condensible gas, oil andrefrigerant vapor mixture from shell 16 into spray pipe 50. The mixtureis sprayed over a coil structure 53 in which is circulated coolingwater, the arrangement being such that the refrigerant is liquified soas to collect at the bottom of the purge drum. The non-condensibles arevented from the purge drum to the atmosphere through a conventionalrelief valve 55.

The purge drum is provided with a central partition 57, which has thefunction of requiring the vapor from pipe 50 to circulate around coilstructure 53 without traveling immediately to the right end-of the drum.This arrangement insures a good heat exchange condition whichcontributes to complete liquification of the condensibles and separationof the non-condensibles.

During operation, moisture and the lighter condensibles are deposited asa liquid layer 60 on the upper surface 61 of the liquified refrigerant.The lighter materials in layer 60 have a lesser specific gravity thanthe liquified refrigerant; consequently the liquid surface 62 to theleft of partition 57 is slightly above the liquid surface 63 to theright of partition 57. A valved drain tube 64 extends into the purgedrum and terminates at a point above the level of surface 63 so as todraw off the layer 60 liquid.

The liquid level 63 is maintained constant by means of a valve 65, whichcontrols the escape of liquid from drum 51 into a line 66. Valve 65 isoperated by a float 67 in such manner that as surface 63 tends to rise,float 67 moves valve 65 to an open position, and as surface 63 tends tofall fioat 67 moves valve 65 to a closed position. Partition 57maintains a stable gas pressure in the space above float 67 so as topermit accurate operation of valve 65.

Line 66 leads into tank 47 to connection with a heat exchange tube 70. Alubricant line 71 extends from the bearings of compressor 10, into tank47, and axially through tube 70 so as to discharge oil into the tank toa normal level 90.

In a typical installation the oil in line 71 is at a temperature ofabout F which is sufiicient to vaporize the refrigerant vapor in tube70. The oil associated with the refrigerant remains in a liquidcondition and fills tube 70 to a level above line 71 so as to promoteheat transfer. Some of the oil in tube 74 becomes entrained with thevaporized refrigerant fiowing out through discharge pipe 72. Thevelocity of the vapor after it leaves pipe 72 is considerably reduced sothat the entrained oil separates out in droplets, which gravitate intothe main body of oil 74. The refrigerant vapor in the space above oilbody 74 is discharged from tank 47 into a line 76, which connects withthe main refrigerant line 43 leading to compressor 10. If desired line76 may connect to the evaporatoror other low pressure area in thesystem.

The flow of lubricant in the system is effected by an oilimmersed pump 78, which is driven by motor 79. Pump for supplying the compressorbearings with lubricant. Line 71 returns the lubricant from thecompressor hearings to tank 47. During operation of the system some ofthe lubricant in the bearings becomes entrained'with the refrigerantpassing through the compressor. However this entrained lubricant issubsequently removed in tube 70 and tank 47; hence the lubricant isprevented from accumulating in the system.

Fig. 2 illustrates a construction which may be used in the Fig. 1 systemin place of heat exchange tube 70. In the Fig. 2 arrangement line 66discharges into tank 47 at a point directly above a small receptacle 82,which receives hot lubricant from pipe 71. As the refrigerant oilmixture strikes the hot lubricant in receptacle 82 the refrigerant isvaporized. The lubricant spills out of the receptacle into tank 47 tomaintain oil level 90. If desired a small electric heater 83 may beemployed to maintain vaporizing conditions above the receptacle.

The illustrated mechanisms for removing the oil and non-condensibles arecomparatively inexpensive to manu- "facture. At the same time themechanisms are efficient in I their operation so as to prevent anypossibility of damage to the refrigerating system. Additionally themechanisms require a minimumof maintenance and parts replacement.

I claim:

1. The combination comprising a refrigerating system including arefrigerant compressor, condenser and evaporator; a lubricantcirculating circuit for the compressor bearings; means for divertingnon-condensibles and vaporous refrigerant from the system; meansoperative on the diverted refrigerant and non-condensibles to liquefy-the refrigerant and separate off the non-condensibles; and means forreturning the diverted liquefied refrigerant back to the refrigerantsystem; said lubricant circuit including means for positioning hightemperature lubricant in heat transfer relationship with the divertedliquid refrigerant to thereby vaporize said refrigerant before itsreturn to the system.

2. The combination of claim 1 wherein the lubricant circuit comprises alubricant supply tank; and the means for returning the liquefiedrefrigerant includes a refrigerant liquid line discharging into saidsupply tank so that the refrigerant is vaporized by the lubricant.

-3. The combination of claim 1 wherein the lubricant circuit comprises alubricant tank and a lubricant pump therein; and wherein the refrigerantdiverting means comprises a refrigerant pump physically located withinthe lubricant tank. v

4. The combination of claim 3 and further comprising a single powermeans for driving the lubricant pump and refrigerant pump.

5. In a refrigeration system the combination comprising a refrigerantcondenser; a refrigerant centrifugal compressor connected directly tothe condenser, a lubrication system including a lubricant tank forsupplying lubricant to the compressor bearings; a purge chamber forremoving non-condensibles from the refrigerant; a first line from thecondenser to the purge chamber; cooler means in the purge chamber forliquefying the refrigerant discharged from said line; a centrifugal pumpin the first line to direct non-condensibles from the condenser to thepurge chamber, a vent means connected to the purge chamber for 'removingthe non-condensibles from association with the 4 a refrigerantcondenser; a refrigerant centrifugal compressor connected directly tothe refrigerant condenser, a lubrication system including a lubricanttank for supplying lubricant to the compressor bearings; a purge chamberfor removing non-condensibles from the refrigerant; a first line fromthe condenser to the purge chamber; cooler means in the purge chamberfor liquefying the refrigerant discharged from said line; a vent meansconnected to the purge chamber for removing the noncondensiblesfromassociation with the refrigerant; a second line from the purge chamberto the lubricant tank; a receptacle within the lubricant tank positionedbelow the point of discharge of the second line; a third line from therefrigerant compressor to the receptacle whereby lubricant from thecompressor is enabled to flow into the receptacle so as to vaporizerefrigerant being discharged from the second line, and a line associatedwith the receptacle in the lubricant tank to direct vaporizedrefrigerant to the centrifugal compressor. i i

7. In a refrigeration system the combination comprising a refrigerantcondenser; a refrigerant centrifugal compressor connected to therefrigerant condenser, 'a lubrication system including a lubricant tankfor supplying lubricant to the compressor bearings; a purge chamber forremoving non-condensibles from the refrigerant; a first line from thecondenser to the purge chamber; cooler means in the purge chamber forliquefying the refrigerant discharged from said line; a vent meansconnected to the purge chamber for removing the non-condensibles fromassociation with the refrigerant; a partition within the purge chamberforming two connected cavities; said cooler means being located in theupper section of one of said cavities; a second line from the othercavity to the lubricant tank; float-operated valve means for controllingliquid flow into said second line when the liquid level in the othercavity reaches a predetermined level; a drain tube extending into saidone cavity and terminating at a point above the aforementioned level,whereby to draw off water which may accumulate in said one cavity; meansfor vaporizing the liquefied refrigerant as it enters the tank from thesecond line, and a lineto direct vaporized refrigerant back to thecentrifugal compressor.

8. In a refrigeration system the combination comprising a refrigerantcondenser; a refrigerant centrifugal compressor connected to therefrigerant condenser, a lubrication system including a lubricant tankfor supplying lubricant to the compressor bearings; a purge chamber forremoving non-condensibles from the refrigerant; a first line from thecondenser to the purge chamber; cooler means in the purge chamber forliquefying the refrigerant discharged from said line; vent meansconnected to the purge chamber for removing the non-condensibles fromassociation with the refrigerant; a second line from the purge chamberto the lubricant tank; a condensible and non-condensible gas centrifugalpump located within the lubricant tank and connected into the firstline; a lubricant pump within the lubricant tank; a third line from saidlubricant pump to the compressor bearings; a motor within thelubricating tank for operating said pumps; means for vaporizing theliquefied refrigerant as it enters the tank from the second line, and aline to conduct vaporized refrigerant to the centrifugal compressor 7 9.In a refrigeration system the combination comprising a refrigerantcondenser; a refrigerant centrifugal compressor connected to thecondenser, a lubrication system including a lubricant tank for supplyinglubricant to the compressor bearings; a purge chamber for removingnoncondensibles from the refrigerant; a first line from the condenser tothe purge chamber; cooler means in the purge chamber for liquefying therefrigerant dlscharged from said line; a vent means connected to thepurge chamber for removing the non-condensibles from association withthe refrigerant; a second line from the purge chamber to the lubricanttank; a heat exc tube Wit in the lubr'nzartttank and connected with thesecond line; a third lubricant line from the refrigerant compressorextending centrally through the heat exchange tube and discharging intothe lubricant tank interior whereby hot lubricant from the compressor isenabled to fiow into the heat exchange unit so as to vaporize therefrigerant in the heat exchange tube, and a line to direct vaporizedrefrigerant to the centrifugal compressor.

10. In a refrigeration system the combination comprising a refrigerantcondenser; a centrifugal refrigerant compressor connected to thecondenser, a lubrication system including a lubricant tank for supplyinglubricant to the compressor bearings; a purge chamber for removingnoncondensibles from the refrigerant; a first line from the condenser tothe purge chamber; cooler means in the purge chamber for liquefying therefrigerant discharged from said line; a vent means connected to thepurge chamber for removing the non-condensibles from associatinn withthe refrigerant; a second line from the purge chamber to the lubricanttank; a centrifugal condensible and non-condensible gas pump locatedwithin the lubricant tank and connected into the first line; a lubricantpump within the lubricant tank; a third line from said lubricant pump tothe compressor bearings; a motor having a double ended drive shaft; saidmotor being positioned between the two pumps with the ends of the shaftdrivingly connected to the pumps; means for vaporizing the liquefiedrefrigerant as it enters the tank from the second line, and a line toconduct vaporized refrigerant to the centrifugal compressor.

Zieber June 15, 1943 Zwickl Mar. 15, 1949

